Licensee Of
Maelstrom High
Shear Mixers - U.K

PRESSURE LEAF FILTER

The Pressure Leaf Filter is a MS/SS Vertical Vessel with Filter Leaves inside. The leaves are mounted vertically on a common manifold pipe, through which the filtered liquid flows out. On the top, the leaves are held by a vibrating shaft . A mechanical vibrator driven by electric motor/pneumatic vibrator is provided for vibrating the leaf shaft for cake discharge. Jacket for hot filtration can be offered if desired Over flow, vent/steam/air charging, pressure gauge & safety valve are provided on the top.

The top cover is provided with devit arm mechanism for raising the lid for cleaning/ removing the leaves. “I” bolts are provided for quick opening and closing of top lid. A mechanical jack is provided to lift the top for cleaning/removing the leaves. Lugs are provided for mounting the PLF.

The Filter leaves filter on both sides and hence a large filtration area is obtained in a relatively small vessel.

Working Of The Pressure Leaf Filter
Leaf Filters are ideal for Solid-Liquid Separation & work on principle of Precoating & pressure. Pre coating is done with the help of suitable filter aid about 0.5 to 1% ( Bleaching earth , supercel, Hyflo, super flo etc.) mixed with the liquid to be filtered. Unfiltered liquid is pumped into the filter vessel. Initially the filter aid starts forming a precoat layer on both sides of the filter leaves, until then cloudy material comes out of the Filter. Once the layer is formed , Pressure starts developing, restricting the impurities. Clear liquid flows from both sides into the leaves ( filter elements), flows along the tubular channel & gets discharged from Bottom of the leaf. All the leaves are mounted on a common manifold. The leaves start getting choked on both the sides by impurities forming cake, which is in wet form. Once the leaves get chocked completely, the pressure rises to 3-4 Kg/cm² & the output flow almost stops.

The Pump is stopped & steam /air pressure is applied from the top ( without dropping the filter pressure) to filter the material around the leaves held up in the tank & to squeeze the cake further & reduce the liquid retention in it . The hold up unfiltered liquid in the conical portion is taken back.

In PLF the cake can be dried by steam /hot air & then discharged from the bottom with the help of mechanical/pneumatic leaves vibrator. The whole operation of cake drying takes 30-45 min, & cake discharge takes 5-10 min.

For wet cake discharge water spray nozzles are provided.

MATERIAL OF CONSTRUCTION

PLF LEAVES

Each Leaf is made of 5 Ply of SS wire mesh of different gauge wires.Two outer filtering mesh are Hollander weaves and three inner Mesh are only for support. The 5 ply wire mesh are held together by a tubular frame & made leak proof by machine riveting. The quality of filtration & life of filter depends mainly on the quality of outer wire mesh & riveting.